The objective of this project is to study the characteristics of animals with congenital defects for clues as to possible relationships to cancer in the same clinic-hospital population, and to relate these findings to man. A file of animals with congenital defects, reported to the Veterinary Medical Data Program (NCI-4371) from March 1964 through January 1969, has been related to the population of all patients seen during the same period. Data received since January 1969 can be used to test the conclusions of studies made for the earlier period. General findings have already been published, and currently, individual species and diagnoses are under scrutiny. Currently popular laboratory animals are generally poor models for genetic disease and congenital malformations in man, and the rarity of these individual conditions in the human population limits clinical research. Our project attempts to detect conditions spontaneously occurring in domestic animals which are more nearly homologous to human afflictions. Since certain congenital malformations in man are associated with childhood malignancies, we hope to identify domestic animals which may serve as research models to explore the borderland between teratology and oncology. Data will continue to come from the Veterinary Medical Data Program and will be analyzed for breed-specific lesions.